Theory Of Operation
The location of the retractor tensioner (driver sill end pretensioner) is within the plastic trim of the B-pillar. The anchor buckle tensioner is an internal part of the seat belt retractor. When powered, the Occupant Restraint Controller (ORC) sends a test current to the squibs to verify the integrity of the squib and wiring. These circuits are maintained in a "floating" configuration at the ORC (connected to neither power nor ground) as protection against inadvertent deployment. Use of the Supplemental Restraints System load tool (special tool #8443A, SRS Load Tool) in the tests below substitutes a suspect squib with a known good component. The SRS Load Tool provides a test point as well as a method for opening the shorting bar connections within the ORC harness connector. The retractor tensioners can not be repaired and if ineffective or damaged the entire retractor tensioner unit is to be replaced. Following any front airbag deployment the retractor tensioners will also be replaced. A growling or grinding sound while attempting to operate the seat belt retractor is a sure sign the retractor tensioner has been deployed and needs to be replaced.